Effect of non-isothermal aging on microstructure and properties of Al-5.87Zn-2.07Mg-2.42Cu alloys
(1. School of Materials Science and Engineering, Central South University, Changsha 410083, China;
2. Key Laboratory of Nonferrous Metal Materials Science and Engineering of Ministry of Education,
Central South University, Changsha 410083, China)
2. Key Laboratory of Nonferrous Metal Materials Science and Engineering of Ministry of Education,
Central South University, Changsha 410083, China)
Abstract: The evolution of microstructure and properties of Al-5.87Zn-2.07Mg-2.42Cu alloys during non-isothermal aging was studied. The mechanical properties of the alloy were tested by stretching at room temperature. The results show that in the non-isothermal aging process, when the alloy is cooled to 140 °C, the ultimate tensile strength of the alloy reaches a maximum value of 582 MPa and the elongation is 11.9%. The microstructure was tested through a transmission electron microscope, and the experimental results show that the GP zones and η'''' phases are the main strengthening precipitates. At the cooling stage, when the temperature dropped to 180 °C, the GP zones were precipitated again. Besides, the experimental results show that the main strengthening phase during non-isothermal aging is η'''' phases.
Key words: Al-Zn-Mg-Cu aluminum alloy; non-isothermal aging; η'' phases; mechanical properties